1. Field of Invention
The present invention relates to image processing methods and an image processing apparatus that processes data to be output to an image output apparatus, such as a liquid crystal display panel, an electronic device provided with the image output apparatus, an image processing program for the above-described image processing, and a recording medium on which the program is recorded.
2. Description of Related Art
Generally, a monochromatic or color liquid crystal display (LCD) panel is used for an image display unit of, for example, a cellular telephone or a portable information terminal. On this LCD panel, when a driving voltage which is preset according to the grayscale value of grayscale data is applied to each of the pixels arranged in a matrix, the transmittance or the reflectance of the liquid crystal is changed in a stepwise manner. Accordingly, by controlling the voltage applied to each pixel, a desired multi-level image is output and displayed.
For the grayscale control for the LCD panel, a frame rate driving method (also referred to as the “frame rate control driving method”) may be employed. In this frame rate driving method, by distributing a halftone grayscale which can be implemented over a plurality of frames in time dimension, halftone grayscale which would not be implemented in one frame can be implemented in one frame. According to this technique, the number of levels which can be represented on the LCD panel (in view of the above-described plurality of frames) is substantially increased.
According to this frame rate driving method, however, various factors, such as the frame frequency, the grayscale value of the grayscale data, the inverter frequency of an auxiliary light source (such as backlight), etc., may cause defects in displayed images which can lower the quality of a displayed image. These defects can include the so-called flickering or fluctuation.